Theory suggests Earth’s pivotal catastrophes can be understood through depth dimension
Theory suggests Earth’s pivotal catastrophes can be understood through depth dimension lead image
Over the course of Earth’s billions of years, numerous events have drastically transformed the planet. The Great Oxygenation, the Snowball Earth and the Mass Extinctions were all pivotal, but remain enigmatic to researchers. A new hypothesis posits the depth dimension of Earth helped lead to all these events in the past -- and will determine the planet’s future.
David Mao and Wendy Mao call their theory the four-dimensional Earth system, or 4D Earth. Through a long career of studying the chemical and mineralogical composition in the deep interior of the planet, David Mao noticed there were “zones” being governed by significantly different processes. The inner and outer zones could be delineated approximately at the middle of the lower mantle.
“I began to realize that the depth dimension actually controlled the whole Earth processes,” said Mao.
An understanding of this depth dimension required years of study.
“The enabling high-pressure techniques to reach the pressures and temperatures of the deep lower mantle and the diagnostic techniques to probe physical and chemical properties in-situ at high P-T took me 50 years to develop,” he said.
The results showed the inner zone follows a pressure-induced physics and chemistry contrasting the conventional processes of the outer zone. The researchers believe this difference causes a physical potential between the two zones, which is the driving force behind catastrophic events such as colossal volcanic eruptions and atmospheric large oxygen fluctuations.
“The paper set up a pursuit of understanding the 4D Earth system through a unified theory,” said Mao. “Once completed, it will have the transformative impact comparable to the plate tectonics theory that has unified the two dimension Earth surface.”
Source: “Key problems of the four-dimensional earth system,” by Ho-kwang Mao and Wendy L. Mao, Matter and Radiation at Extremes (2020). The article can be accessed at https://doi.org/10.1063/1.5139023 . This paper is part of the High Pressure Science Collection, learn more here .
